Helicopter rotor



NOV- 10. 1953 PloTR F LAPlDovsKY Now EY JUDICIAL CHANGE oF NAME PETER T. STONE HELICOPTER ROTOR 5 Sheets-Sheet l Filed July 1'?, 1946 Nov. 10, 1953l PloTR F. LjAPlDoVSKY 2,558,575

\ Now BY JUDlclAu CHANGE oF NAME PETER T.STONE HELICOPTER ROTOR Filed July 17, 1946 5 Sheets-Sheet 2 i INVENTOR. :P1/tm T 313% OVSKY Nov. 10, 1953 PloTR F. LAPID 2,658,575

Now BY JUDICIAL CHANGE oF NAME 'f PETER T. STONE HELICOPTER RoToR Z5 Sheets-Sheet 3 Filed July 17, 1946 INVENTUR.

#Tx/JIMA YM jatented Nov. 1G, 1953 OFFICE HELICOPTER ROTOR Piotr F. Lapidovsky, now by judicial change of name Peter T. Stone, Wilmington, Del.

Application July 17, 1946, Serial No. 684,373

7 Claims.

This invention relates to helicopters, and is particularly concerned with the blade mounting, where either one or two sets of rotating blades is used.

The principal object of the invention is to provide a blade mounting where the blades are tiltable as a unit about a point which is midway between a set of rotating blades and in axial alinement therewith.

Another object of the invention is to provide a blade assembly where two sets o1l blades rotate in opposite directions, and are tiltable as a unit about a point which is midway between the lower set of rotating blades and in axial alinement therewith.

Another object or the invention is to provide an improved assembly for either a single set of rotating blades or a double set, where the two sets rotate in opposite directions, as usual.

Another object of the invention is to provide an improved mechanism varying the angle of incidence of each of the blades, whether a single set or a double set is used.

Reference is now made to the accompanying drawings illustrating the preferred way of carrying out the invention.

In these drawings:

Fig. l is a central vertical longitudinal section of the helicopter, taken substantially on line l-i of Fig. 3

Fig. 2 is a horizontal section taken on line 2---2 of Fig. l;

Fig. 3 is a horizontal section taken substantially on line 3--3 of Fig. 1;

Fig. 4: is a perspective view of a lock plate;

Fig. 5 is a detail perspective view of the upper hub and portions oi the attached axles;

Fig. 6 is a sectional perspective view of the central drive shaft structure;

Fig. '7 is a sectional perspective view of the innermost, revoluble rocking bearing member;

Fig. 8 is a perspective View, partly in section, of the iirst, innermost rocking member;

Fig, 9 is a perspective View, partly in section, of the outermost rocking member;

Fig. 10 is a detail perspective view of one of the plate inserts for the rocking members, serving to retain the trunnions in bearing positions;

Fig. 11 is a fractional perspective View of the mid-hub showing the arrangement of the actuating arm;

Fig. 12 is a cross section taken on line I2-I2 of Fig. 1;

Fig. 13 is a schematic view oi the rotor system and the feathering mechanisms therefor.

(Cl. TIO-135.26)

Referring now particularly to Fig. 1, 2 is the main supporting ring which is integral with or secured to downwardly extending arms d, which are attached to the fuselage. Mounted just with in ring E is the outer gimbal ring t having oppositely extending pivots 6', t', pivotally mounted in suitable recesses in the main ring 2. 8 is an inner gimbal ring mounted just within ring ti, and provided with outwardly extended pivots 8', pivoted in suitable bearings in the outer ring 5. The axes defined by pivots 6', 6 and S', il are at right angles to each other. Mounted just within the inner gimbal ring 8 is an inner supporting ring d, having outwardly extending pivots l,

mounted in bearings in the inner gimbal ring t.

For convenience in assembling the pivots ill in ring S, or pivots 8 in ring 6, the ring to receive the pivot may be recessed as shown at l, Fig. 9, to receive a bearing tting El, Fig. l0. recess l ins cluding slots l' for receiving shoulders d on the fitting.

A main annular rotatable drive collar il is mounted within ring Iii, and extends for some distance above it. This collar il has annular flanges i3 and lll cooperating with suitably formed portions of the ring iii to denne raceways for ball bearings i5 and i6.

An annular housing or dome i8 is keyed to the upper part of the main drive collar i i by keys 2i), so that dome i8 is rotated by the drive collar il.

The main drive collar Ei and dome or casing I3 are driven, preferably clockwise, by a vertical drive tube i2, see Fig. 6, driven by the engine. This tube has forks 22 in which are seated pins 2li projecting from ring 2li. Ring 25a has another pair of pins 25 which are seated in oppositeiy located sockets 2@ carried on the interior of drive collar il. Rotation of tube 22 therefore drives collar li and dome i3.

Dome i8 supports and drives the bearing housing 3G for the lower helicopter blades S2.

In order to tip the blade assembly for steering in one direction, ring it, Fig. 7, is provided with a downwardly extending control arm 3s, attached to the`1ower edge thereof; by actuation of this arm, the ring I@ and the blade assembly may be tilted about pivots iii. In order to tip the blade assembly for steering in another direction, ring il, Figs. 1 and 8, is provided with a downwardly extending control arm Sil, by actuation o1" which ring 8 may be tilted about pivots d', a matter of 20-30 or so. Arm 325 may be laterally offset as shown in Figure 7 to avoid tube 22. Arm 38 may be similarly offset.

From the described construction, the supporting and driving assembly for the lower blades 32 is free to pivot in any direction about the point P, which point is at the intersection of axial lines drawn through pivots ID', l0 and 8', 3. This point would also be located at the center of ring 24 and would be in line with and directly above the center of gravity of the entire helicopter, including the fuselage, engine, fuel tanks, etc.

The blade assembly for the upper set of blades is supported, and driven in the opposite direction, by a main shaft 40. This shaft is journaled or swiveled inside collar ll; the lower portion of shaft 40 is flanged, and collar Il is correspondingly shaped or grooved to provide raceways for ball bearings 42; further up, these parts are formed to provide raceways for ball bearings 44.

In order to drive shaft 49, drive tube 46, driven from the engine, is provided with a fork 48, Fig. 6, in the ends of which are seated pins 53', projecting from ring U; ring 5D carries two other pins 5I, engageable with a pair of forked members 52 secured to and projecting down from shaft 40. Lines drawn through the axes of the pins 50' and 5l would pass through point P.

The hub 54 for the upper set of blades is keyed to the upper end of shaft 49 by key 55 and is held in place by nut 56, the nut being locked in place by a U-shaped locking plate 5l, Fig. 4, having a hexagonal hole 56 for nut 55. The hub carries a shaft or tube 58, on the outer part 59 of which is journaled the housings 50 for the upper blades 62.

The angle of incidence of all four blades is varied by hydraulic or pneumatic means. This comprises the mechanism shown in Fig. l, and shown diagrammatically in Fig. 13.

The angle of incidence of the blades is controlled by movable control arms 62' for the blades 62, and by control arms 32' for the blades 32, these control arms being connected by bolts 64 to brackets 66, carried by and extending outwardly from blade housings 60 and 30.

The upper control arms 62 are pivoted to the outer ends of actuating arms 63, secured to or integral with a collar 'l0 surrounding shaft 40, so as to be movable a few inches up or down on the shaft, on ball bearings 12. This up and down movement of collar l0 is effected by a piston rod 14, pivoted at 14 to an arm 68, the piston rod having a piston working in a fluid pressure or pneumatic cylinder 16, held in place by arm 18. To increase the angle of incidence, uid under pressure, such as oil or air, is supplied by pipe 80 to cylinder 16. When the fluid pressure is lessened, the reaction of the air on the blades reduces the angle of incidence. Fluid under pressure is supplied to pipe 89 from a central passage 82 in shaft 45, connected by a swivel connection 84 to a flexible, high pressure hose 86, leading to a suitable manual pressure control in the fuselage.

Arms 68 must turn with the helicopter blades; accordingly, they are linked to the hub 54 by heavy double links 38, pivoted at 89 to arms 68, and by similar links 9i), conveniently pivoted at 9| to brackets 9|', Fig. 4, carried by plate 5l. The pair of links are pivoted to each other at 92. This linkage still permits up and down movement of collar 19 on shaft 40.

The other two actuating arms 93, for the blades 32, which rotate in the opposite direction, are connected with la collar 94, which is swiveled on collar 1U by ball bearings 95. These arms 93 are driven and steadied by heavy double links 96, `pivoted by pins 91 to heavy lugs 98 projecting from the outer surface of dome I8. Double links 99 are pivoted by pins l0!) to lugs IDI formed on the underside of arms 93. Links 96 and 99 are pivoted to each other by pins H12. Since the collars 'l0 and 94, for the respective upper and lower actuating arms 68 and 93, are secured together, the piston rod 14, when pressure is applied, moves both collars, downward movement increasing the angle of incidence of all the helicopter blades; when the pressure is relieved, all blades will decrease their respective angles of incidence, due to the reactive effect of the air.

Summary of the operation Referring particularly to Fig. I, blades 32 `are rotated in one direction by outer drive tube 22, which in turn drives ring 24 and main drive collar Il. Collar Il drives dome I8 and blade housings 39 of the blades 32.

Blades E2 are rotated in the opposite direction by inner drive tube 46, which in turn drives ring 50 and drive shaft 49 and hub 54 for the upper set of blades, in the opposite direction.

rihe angle of incidence of each of the upper and lower blades is controlled by collars 'I5 and 94, which, while rotating in opposite directions, move as one up and down on shaft 46 a matter of a few inches, and move the upper actuating arms G8 and lower actuating arms 93, which cause all the blades to turn about their longitudinal axes in unison and in the same sense, that is, to greater or lesser angles of incidence.

The fulselage is suspended from the blade assembly by arms 3, the blade assembly being tiltable by control arms 36 or 38 about axes at right angles to each other. This tilting takes place about the point P, which may be regarded as at substantially the center of gravity of the assembly of the two lower blades 32 and their cooperating mechanism. That is to say, where only one set of blades, such as 32, is used, such single set of blades would pivot about the center of gravity of the assembly, which is at the point P. This point P is also in substantial vertical alinement with the center of gravity of the fuselage and its load, considered as a unit.

When a double set of blades is used, for greater lift, the reactive torque of one set balances the torque of the other set and the gyrosccpic forces balance each other. The center of gravity of the double set assembly would be in the center of shaft 49, at about the level of collar 'Fl Tilting about point P, however, would displace this upper center of gravity only a very small amount out of the vertical, so that proper balance and control of the entire helicopter1 fuselage and all, is not affected.

As will be apparent to one skilled in the art, the described controls may be actuated automatically, as well as manually.

While the preferred construction of the helicopter has been shown in detail, it should be understood that the invention is not limited to the exact details shown, but may be carried out in other Ways.

I claim as my invention:

l. In a helicopter, a pair of supporting arms extending downwardly to the fuselage, a pair of cooperating gimbal rings pivoted between the upper ends of said arms, a supporting ring, pivoted within the inner ring of said pair of gimbal rings, a drive collar rotatably mounted within said supporting ring, a dome member driven by said collar, a lower set of helicopter blades carried by and driven by said dome member, an upwardly extending vertical shaft journaled in said drive collar, an upper set of helicopter blades carried by and driven by the upper part of said vertical shaft, a universal joint for driving said drive collar, a second universal joint at the same level for driving said upwardly extending shaft, said universal joints being at the same level as the axes of said pair of gimbal rings, means for driving said universal joints in opposite directions for thereby rotating the two sets of blades in opposite directions, the entire assembly being tiltable about the center of said two universal joints.

2. The combination as set forth in claim 1, wherein the blades are axially tiltable, and further including a collar slidable on the intermediate portion of said upwardly extending vertical shaft, and means operatively connecting said slidable collar to said axially tiltable blades, whereby movement of said collar above said shaft serves to tilt all the blades for simultaneously varying their angles of incidence.

3. The combination as set forth in claim 1, wherein one of the cooperating gimbal rings that mount the lower set of helicopter blades is each provided with a downwardly extending control arm, a second control arm secured to said supporting ring, said control arms being set 90 apart, for eifecting tilting movement of the entire assembly of lower and upper blades.

4. In a helicopter, means, including a dome member and a pair of cooperating gimbal rings, for mounting a lower set of helicopter blades for universal tilting movement, a supporting ring, pivoted within the inner ring of said pair of gimbal rings, a drive collar rotatably mounted within said supporting ring, and xed to said dome member, a vertical drive shaft rotatably mounted within said drive collar, a second set of helicopter blades keyed to and driven by the upper part of said vertical drive shaft, a pair of concentric vertical oppositely driven members, and a pair of universal joints, respectively connecting the upper ends of said oppositely driven members to said drive collar and to said vertical drive shaft, for thereby driving the two sets of helicopter blades in opposite directions.

5. The combination as set forth in claim 4, wherein the blades are tiltable on their own axes, and further including a collar slidable on the intermediate portion of said upwardly extending shaft, and means operatively connecting said slidable collar to the axially tiltable blades, whereby movement of said collar along said shaft serves to vary the angles of incidence of all the blades.

6. The combination as set forth in claim 1, wherein said center of said universal joints is in vertical alignment with the center of gravity of the helicopter.

7. The combination as set forth in claim 4, wherein said vertical drive shaft is in vertical alignment with the center of gravity of the helicopter.

PIOTR. F. LAPIDOVSKY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 954,574 Koegler Apr. 12, 1910 1,294,361 Nash Feb. 11, 1919 1,656,468 Braugh Jan. 17, 1928 2,037,745 Vaughn Apr. 21, 1936 2,074,342 Platt Mar. 23, 1937 2,156,334 Bothezat May 2, 1939 2,163,893 Schairer June 27, 1939 2,230,811 Pecker Feb. 4, 1941 2,264,943 Larsen Dec. 2, 1941 2,394,846 Cox Feb. 12, 1946 2,415,999 Frasher Feb. 18, 1947 2,440,225 Pullin Apr. 20, 1948 2,444,070 Stanley June 29, 1948 2,450,491 Solovioff et al Oct. 5, 1948 

